Improvement in apparatus for feeding pulverized fuel to furnaces



6 Sheets-Sheet 1. T. R. ORAMPTON. APPARATUS P93 FEEDING PULVBRIZBD FUEL T0 FURNACES.

Patented Feb. 7, 1871.

6 Shets8heet 2.

- T. R. GRAMPTON. APPARATUS FOR FEEDING FULVERIZED FUEL T0 FURNACES.

Patented Feb. 7, 1871.

o 1X11 A 7J 7/24 7% 7 W A 6 Sheets-Sheet 3.

T. 11011111111011. APPARATUS FOR FEEDING FULVEEIZED FUEL T0 FURNACES.

110111514. Patented Feb. 7, 1871.

6 Sheets-Sheet 4 T. R. (BRAMPTON. APPARATUS FOR FEEDING PULVBRIZED FUEL T0 FURNACES.

a a a a 6 Il 1/ W W I 7 b 6 P 1 1 1 e m P l I m T J/Imd4 Mam/6A:

6 Sheets-Sheet 5.

T.R.-ORA1V1PTON. APPARATUS FOR FEEDING PULVBRIZED FUEL TO FURNACES.

No. 111,614. Patented Feb.-7, 1871.

6 -Sheets8heet 6.

T, R. BRAMPTON v APPARATUg FOR FEEDING PULVBRIZBD FUEL T0 FURNACES.

Patented Feb THOMAS- R'USSELL ORAMPTON, OF WESIMINS'IER, LONDON', QREA'I BRITAIN.

Letters Patent No. 111,614, dated February 7, 1871. IMPROVEMENT IN APPARATUS FOR FEEDING PULVERIZED FUEL TO FURNACES.

The Schedule referred to in those Letters Patent and making part of the same.

Know all men by them: presents.-

lhat I, Tnonas' Russnnn Unnnrrro'x, of Westininster, London, in the county of Middlcsex, in the Kingdom of Great. Britain, have invented cer tain new and useful Improvements in the method of burning pulverized fuel and in apparatus and furnaccs therefor; and I do hereby declare the following to be a full, clear, and exact description, which will enable those skilled in the art to construct and use the some.

I do not pretend to have discovered that a solid fuel, when reduced to powder and combined with a due proportion of atmospheric air, and suiliciently heated at first, and ignited in a proper chamber, may, it'the supply is steadily kept up, continue thereafter in combustion.

Others have discovered this before me, and have described various devices for accomplishing the object. SOUIGIHWO used what is called carbonized air in the reduction of ores, and for other purposes; some have used it in blast-furnaces; others, again, have described it in connection-with devices for producing combustion without reference to its application; some have sprinkled the pulverized fuel on the ore already heated in the culinary way; others have depended for their results uponconverting the solid fuel into an impalpablc powder, to which the term floating might be applied, and have described the fuel so linc that seventy-live per cent. would pass through a screen of ten thousand holes to the inch, that is, the particles of line coal are about the one-lnimlreth part of an inch in diameter, the efficiency of the device depending on this excessive fineness some have prothrough a single pipe into the chamber in which it was to be burned; others have branched the main pipc,.making t-hc carbonized air enter the combustion-chumher at different points so as to diffu e the heat over a larger area; one-and all, however, seem to have depended either upon the heat from solid fuel, or upon a properly regulated supply of carbonized air, to maintain, iml;pemlently of solid fuel, a. continuous combustion.

The devices for which I now desire Letters Patent belong to the latter class, but are altogether novel, not. only in their form and arrangement, but in the principles upon which they operate in producing, rcgulating, controliifig, and directing the desired combnstion.

I. introduce six or ei ht or more or less accordin P 'to the size of the finance, streams of carbonized air at the back 01' a-cornlmstioinchamber, which has-n plain solid bottom without lirc-baisor divisions cl any kind, through openings near to each other and on the same plane, so that the streams of carbonized air as they expandon leaving their respective pipes or openings comminglc, insuring a greater uniformity of combination between the air and fuel than can be effected either with a single pipe or with branches from a single pipe opening into the combustion-chamher at placesitoo remote from each other to permit the sullicient, commingling of the carbonized streams of air. I

And still further, to promote the perfect combination of fuel with air, I construct the bridge-wall with a suitable slope toward the openings, so that the commingicd streams of carbonized air impinging' on it at an angle spread in all directions, when there is a further conuningling, and a combination of air and fuel homogenons in its character is deflected over the bridge-wall ready to do its work in the furnace to which these devices have been applied. It will thus be seen that instead of relying upon the combination of air and fuel escaping from a .single pipe as snliicicntly perfect to secure, when once ignited, a continuous and uniform combustion, I'subject the carbonized air as it escapes ti-om each pipe,

First, to the action of similar streams from adjacent pipes; and

Second. to the impingement upon the bridgeuvoll, as a-loresaid, or even upon the bottom of the coinbustion-chamber, in order to produce that homogeneity of combination upon which a perfect combustion -is altogether dependent.

The use of these devices makes my invention independent of that excessive fineness of pulverization which, it is said, is necessary to the success of some of the other inventions aiming at the same results.

To prepare the fuel used in the devices of Messrs. Whelpley aml Storer, various contrivanccs for pulvcrizing ithave been patented by them, all looking to extreme lineness, while for my devices the products of connnon millstones sntlice.

But it is not only necessary that the commingling which 'my devices provide for should take place, but that the quantities of carbonized air passing from the several pipes into the combustion-chamber should'hc, as nearly as practicable, equal.

Accordingly the fuel, ground to the required fineness, is placed -in a rectangular reservoir, located above. the'planeof the pipes albrcsaid. In this there are rotating stirrcrs which urge the fuel through a gate at one end of the reser'voir and upon a roller, a part of whose periphery forms the bottom of a box attached to the rescrvoiraud supports the fuel issuing iron] the gate.

Above the roller, just described, is another and the chamber at starting only sufficiently to ignite the smaller one, apart of whose periphery is within the box; the two rollers by a proper gearing being made to move at about the same surface speed. T

The space between the faces of these rollers is adjustable, aml receives the pulverized fuel passing through the gate of the reservoir and delivers it in a thin sheet of grains of uniform density into a trough, from which descend as many recciving-tuhcs as there are conducting-tubes leading to the furnace.

The upper openings of the receiving-tubes in the. trough are rectangular, and so closely arranged side by side as to divide equally the sheet of grains falling into them into as many portions as there are conducting-tubcs.

,The bottom of the receiving-tubes is circular, and they are united each to its separate conducting-tube it little in advance of its outer and open end.

Having thus secured to each conducting-tube an equal supply of fuel, 'the next thing to be done is to combine or mix it with atmospheric air, and to force the combination, which will then be carbonized air, into the combustion-chamber. This is effected by a. fun or other contrivance that may be employed to supply the blast of air required, which is forced into a, cylinder in the same plane with the conductingt-ube's, opposite to the open ends of which are as many air-nozzles.

These nozzles are smaller in diameter than the open ends of their respective tubes and at a short distance therefrom, so that there is a space into which the external air may enter into the conducting-tubes along with that which is forced into them from the airnozzles.

From this description, the operation of the devices I have invented,-to secure the perfect combustion of pulverized fuel in a combustion chamber without other aid from solid fuel than may be necessary to heat streams of carbonized air on their first entrance, will be readily understood.

The stirrers in the reservoir of pulverized fuel forward it to the gate, where, passing over a part of the lower roller, it received between the two, and leaves them in 'a thin Bbect'of grains which fall into the receiving-tubes, descend into the comlucting-tuhes, and then, driven forward by the current of air from the air-nozzles and the external air that esters with it, are earried, cominingled with air, to the furnace, entering which the jets of carbonized air commingle by expansion; and being further commiugied as they impinge on the slope of the bridge-Waller the solid floor of the combustion-chamber, produce a perfect combustion, applicable to any purpose for which such heat may be required.

Havhig thus distinguished my devices from all others, and described them generally and their operation, I will proceed now to describe them more in detail, and explain the drawing that exhibits them, to the end that those skilledin the art may be the better. enabled to construct and use them.

Figure 1 represents a plan of the apparatus for; feeding and iuiectiug the pulverized fuel into the combustion-chamber and furnace.

Figure 2 is a front elevation of the feeding and injeetingapparatus, and a vertical longitudinal section of the furnace.

Figure 3 is an end elevation of the furnace and a. section of the feeding and injecting apparatus.

Figure 4 is a vertical section, showing the relative osithm of the receiving-tubes, th'c air-nozzles, and the conducting-tubes.

Figure 5 in a top view of the pressure blast-charm her with its series of nozzles and their relation to the conductlug-tubes.

Figure 6 in a vertical section at the rooelvln g-tnbes bridge-wall or solid. floor 'tectcd' by ordinary water tuyeres,

showing their connection with the feed-roller and conducting-tubes.-

The same letters represent the same parts in all the figures.

A represents the walls of the furnace.

b B, a plain flatbottom in lieu of the ordinary grate- 0 the combustion-chamber, heated to the proper temperature to ignite the first jets of carbonized air, as above described, by a other fuel.

D, fig. 2, the fire-bridge, sloped, as described already.

D", fig. 1, is a door at the end of the bridge, through which slag maybe removed and the sloping surface of the bridge-wall protected with any fire-resisting materials, renewed from time to time while the. furnace. is in operation.

E, the conducting-tubes, inclined, in fig. 2, so that the carbonized air projecting from themoinay impinge in the direction of the stream 1', fig. 2, upon the slope of the bridge-walla Thes'e tubes, at their entrance into the o'omliustiouchamber, are kept up from the bottom so as to'allow a circulation of heated air below them and through the spaces a, fig. 1, between .them, counteracting the cooling effect of the incoming streams of carbonized air.

In fig. 1 the conducting-tubes are shown with a bend at right angles, and madein sections, to afford faeility in joining them together. This is a convenient form of construction, but not a necessary one. It is convenient because, while the conductlug-tubes enter the combustion-chamber at rightangles at a proper distance from each other, it allows, them to be brought close together under the receiving-tubes without affecting their parallelism, as shown in the drawing, fig. 1.

Nor is their efficiency impaired by this arrangement. The greater specific gravity of the fuel in the carbonized air carries it on the outer interior of the bent tube, and keeping on this side to the mouth, the part of .the stream of each tube that is overcharged with fuel is, with the exception of the outermost tube, next the underchargcd part of the stream of carbonized air ,in the adjacent tube, and the undercharged and the overcharged parts beihg commingled as the streams expand, as already described, the desired homogeneity of combination is promoted, to be perfected as the combined streams impinge on the of the" chamber, as aforesaid.

The arrangement shown in fig.-1 has this recommendation, that it permits the reservoir and its attachments to be placed aside arid out of the way. 'Dho device, however, is independent of this. Ihuvc found that, practically, an inside diameter of' two inches for the conducting tubes, and placing them from five to fire and one-half inches apart, measuring from center to center, where they enter the combustion-chamber, gives excellent results. Their ends may be proor made flush with the outside of the combustion-chamber or a small recess from it, as shown,.in fig. 2, and luted with fireclay.

I have mentioned the distance of five to five and onc-lnlf inches from center to center of the conducting tubes; but a lesser or even a greater distance may answer a good purpose, having regard to the length and depth of the combustion-chamber, velocity and bulk of the streams of carbonized air, and other circumstances far apart that the respective min is, as herein described, cont noting-tubes.

streams will not oomontheir escape from the temporary fire of wood or but "they must never be placed so For the purpose of equalizing the beaten both sides of the furnace the conducting-tubes may he nr-- ranged to enter nearer the side inwhich the doors are in tlic'furnace, as shown in fig. 1, thereby dispensing wit-h'the monkey at the bridge, heretofore used for that purpose; or the-tubes may be central and directed slightly. toward the door side to eflect the-object. V I

Grepresents the receiving tubes, into which the carbon falls from between the rollers L and M, as already described. They are drawn together at their upper ends, which shortens the rollers L' and M, and has other advantages in securing more uniformity in the amount of fuel fed into the receiving-tubes. b and c, fig. 4, represent the sides of what I call the trough in the foregoing description; into which the fuel falls, and in whose bottom are the openings of thereceiving-tubes. he'sido c touches the lower when.

L and M are the feeding-rollers, the ,upper periphery of L being a little above the bottom of the reservoir 0, which projects, as shown at P, of the widthcf the rollers, so as to form a box, into which the stirrers Q-Q forward the fuel. through the opening d against the upper roller M, between which and L it passes in a constant and uniform stream, as already described.

To facilitate this, and to facilitate the inspection of the condition of the carbon in the box P, the axis of 1%,]? shown in the drawing, is in advanceof the axis 0 Thequantity of fuel passing between these roller is regulated, by varying the distance between them,

-by means of a regulating-screw, W, acting on a lever, X, so as to turn a shaft. which carries the bearing-arms of the u per roller.

The feed of the.roliers may be regulated-in many ways; I prefer that which -I have particularly described.

The lower rolicri L is provided with a thin scraper, j, fig'..3, fixed in the box I, adjusted to scrape-the carbon as it passes out from the roller.

The upper roller has a scraper, It, also, hinged 'to the box P, and with a counterbalance, so 'as torest againstrthe roller and detach any particles of fuel that may adhene to and be carried up by'it.

Q, fig. 3, represents the'stirrers in the reservoir 0. They 'are formed by placing suitably-shaped arms on horizontal shafts, and rotated by a belt on the pulley I, or by any ordinary contrivance.

'lhev force the pulverized fuel, through the. opening (1, fig. 3, regulated by a door, i, the top of the opening (Lbeing kept below the top of the box I, so that the fuel passing out is not forced over the top of the box.

Should the box 1 become filled with fuel in consequence of the rollers not taking it away fast enough, the stirrers, not having sufiicient force to increase the height oi" the fuel in the box, will continue to agitate it tiilthe rollers have reduced. the quantity in the box, when it is replenished by the action of the stirrers,

The fuel in the box is always, in this w'ay,in a

comparatively loose state, and at a comparatively uniform pressure, whatever may be the height of the fuel in the reservoir. e c e e are the air-nozzles, with their open ends about one-fourth of an inch .from the open ends of the conducting-tubes, and their centers about onefourth of an inch b'elow the centers of the latter. 'lhis arrangment,.with the position of the receivlog-tubes near the end of the conducting ones, causes the air drawn from without into them, along with that supplied from, the nozzles, to carry the descending fuel into the, conducting tubes better and more nnou surely than if the nozzles were-central with them, and

obviates any tendency of thecnrrent of air o ascend -crcase of the area. of the opening above the nozzles facilitates the draught into the conducting-tubes of any particles of fuel which may have not passed between the rollers and fallen down.

It will be 'secnon'inspection that the nozzles e e e c are smaller in diameter. than the conducting-tubes, which is what allows the outer air to'be drawn in by induction through the space between the two.

S is the air-chamber, supplied from a blast-fan; the velocity of the air being regulated by the valve V in the air-.pipeU.

'A collecting-plate, -Z, fig. 4, may be arranged directly below the air-nozzlcs,'to catch any fuel that may not bedrawn intothe conducting-pipes.

In working furnaces having a partial vacuum there shoukl be snificient force in the streams of carbonized air to enter the furnace freely when the vacuum is reduced by opening the door or otherwise, to prevent the carbon being retained in the conducting-pipes, especially when they are of some length and have bends in them, and also to prevent the fuel from blowing back in cases where it is fed into the tubes close to the furnace or otherwise.

' I have found that in an ordinary heating-furnace,

worked with an ordinary vacuum, in the chimney equal to about one-fourth of an inch of water, when the air without the fuel is forced, at one-half inch pressure. into a cold fumace, the pressure is sutiicient to carry in the fuel when the doors are open during the ordinary working when at full heat.

In proportioniug the conducting-pipes, therefore, reference should be. had to the pressure indicated. frhe'importance'of this point will be understood by, all acquainted with the working of furnaces.

If the furnaceis to he worked undera. pressure oi a few inches of water, or just on-a balance with the outer atmosphere, the pressurev of the streams of carbonized ,air must be increased or diminished according to the pressureused in the furnace.

Furnaces having grate-bars for fixed fuel may be changed into those having plain combustion-chambers by covering the fire-bars with a suitable refractory material, or a plain bottom may be substituted for thefire-bars after they are removed.

I donut claim injecting pulverized fuel into the combustion-chamber of a furnace by means of a blast of'air, gas, or steam passing through one or more tubes, as that has been done; but

What I'do claim as my inventiou-is l. The series of conducting-tubes arranged on the same horizontal level, and grouped substantially as set forth. p

2, In combination with the above,-combiniug, as an additional element, a solid floor without fire-bars, on

. which the streams from the tubes may impinge ornot,

as desired.

3. In combination with the subject matter of the first clause as above, combining as an additional element asioping bridge-wall, as hereinbcfore described, with a view. by, the impingement thereon of the carbonized air'frem the tubes, to promote the greater homogeneity of the combination of the fuel and air entering thecombuetion-chamber from the tubes aforesaid, as they impinge upon it and are deflected upward into the chamber beyond.

4. The combination of the stirrer-s Q in thereservoir 0, the opening d, the box I, and the rollers L and M for delivering a sheet of pulverized fuel in equal quantities into the trough, whose bottom is the open mourns of the receiving-tubes G, arranged as above described.

5. The combination, as additional elements-to the lust clause of claim, of the air-nozzles from the airchainber S, the receiving-tubes and the conductingtubes, the center line of the nozzles being below the center line of the conducting-tubes, as described.

6, The division of a; given quantity of pulverized fuel into equal parts by passing it between adjustable rollers into atrough whose bottom is the open rectangular mouths oi the tubes requiring to be equally supplied with fuel, in the manner herein described.

7. The arrangement of the rollers L and M relatively to the discharge'opemng d in the hopper, so as to form a. limited supply-chamber bet-ween them, as I hereinhcfore described.

8. The arrangement of the receiving-tubes side by sido,\vheu the sheet of pulverized fuel titlls'into thereby diminishing the length of the rollers, and in that manner avoiding too great an attenuation of the shee of fuel passing through them.

'1 R. GRAMPTON.

them,

Witnesses:

'1. HILLAS ORAMPTON,

12 Great George-street, JYestminster. 'lnomrs LLOYD,

12 Great Georgest'rem, Westminster, London 

